宽阻带的人工表面等离子激元微带低通滤波器

Spoof surface plasmon polaritionsmicrostrip low-pass filter with wide stopband

针对传统的人工表面等离子激元(SSPPs)微波滤波器的带外抑制水平较弱的问题,设计并制作了一款采用新颖蝶形结构的小型化SSPPs宽阻带微带低通滤波器。首先,通过将传统的微带滤波器中的扇形结构与SSPPs理论相结合,设计了蝴蝶形结构的SSPPs结构单元,实现了较宽的阻带。为了提升滤波器的带外抑制水平,引入了对向箭头形谐振贴片,抑制了所提出滤波器在阻带内25 GHz处的寄生通带。通过仿真模拟单元结构的色散特性,实现了对SSPPs单元的优化设计。设计了一个完整的SSPPs滤波器结构并仿真分析了关键参数对整个滤波器性能的影响。使用F4B板材制作了金属-介质-金属(MIM)结构的该滤波器并对其性能进行了测量。结果显示,该滤波器的3-dB截止频率为10.08 GHz,阻带的最高频率可达33 GHz;通带内回波损耗均高于15 dB,插入损耗最高为2.6 dB;阻带最小衰减在11~35 GHz的范围内最低为22.98 dB,而回波损耗在10~30 GHz范围内基本优于3 dB,且在10~34 GHz范围内最高为4 dB。本设计的测试结果满足设计指标,带外抑制效果理想,可与混频器、信号发生器等器件集成以发挥更好的电路性能。

To address the issue of weak out-of-band suppression in traditional artificial surface plasmon(SSPPs)microwave filters,a miniaturized SSPPs wide-stopband microstrip low-pass filter featuring a novel butterfly structure is devised and fabricated.Firstly,by integrating the fan structure in the conventional microstrip filter with the SSPPs theory,the butterfly structure of SSPPs is designed to obtain a broader stopband.To enhance the out-of-band suppression level of the filter,an anti-directional arrowhead resonant patch is introduced to suppress the parasitic passband at 25 GHz within the stopband.The optimal design of the SSPPs unit is accomplished by simulating the dispersion characteristics of the unit structure.A complete SSPPs filter structure is designed,and the impact of key parameters on the performance of the filter is simulated.The metal-medium-metal(MIM)structure of the filter is fabricated using F4B substrate,and its performance is measured.The results indicate that the 3-dB cut-off frequency of the filter is 10.08 GHz,with the highest stopband frequency reaching 33 GHz.Return loss within the passband consistently exceeds 15 dB,while maximum insertion loss within this range is measured at 2.6 dB.Notably,minimum attenuation within the stopband measured at 22.98 dB between 11~35 GHz,with return loss generally exceeding 3 dB across the range of 10~30 GHz and peaking at 4 dB from 10~34 GHz.The test results of this design meet the design index,the out-of-band suppression effect is ideal,and it can be integrated with mixers,signal generators,and other devices to exert a superior circuit performance.